In the related art, when one door glass in a back seat is completely or partially opened at the time of driving a vehicle, a part of an air flow climbing over a center pillar is in contact with a rear pillar or a division channel, thereby generating a drone noise of a rear door glass. The drone noise gives a passenger a severe unpleasant feeling to trigger a headache by pressing a passenger's ear rather than a noise to be harsh to the car.
In order to reduce the above-mentioned drone noise of the rear door glass, there was proposed a method of preventing the air flow from being in direct contact with the rear pillar or the division channel by allowing the air flow to be raised upwards by a deflector at the time of driving the vehicle by fixedly installing the deflector in a rear door frame to be inclined upward to the rear of the vehicle at a predetermined angle, in prior art. However, in this method, there was a disadvantage in that the deflector is installed in the rear door frame to protrude to the outside of the vehicle, thereby degrading an exterior of the vehicle and a wind noise is rather generated by the deflector at the time of driving a vehicle at a high speed with the rear door glass closed.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.